Leather-like cloth and its preparation



Nov. 1, 1966 TETUYA lSEKl 3,282,721

LEATHER-LIKE CLOTH AND ITS PREPARATION Filed April 16, 1964 4 Sheets-Sheet 1 Nov. 1, 1966 TETUYA lSEKl 3,282,721

LEATHER-LIKE CLOTH AND ITS PREPARATION Filed April 16, 1964 4 Sheets-Sheet 2 INVENTOR BY 00W 411; M ATTORNEY) Nov. 1, 1966 TETUYA lSEKl 3,282,721

LEATHER-LIKE CLOTH AND ITS PREPARATION Filed April 16, 1964 4 Sheets-Sheet 5 INVENTOR BY MW *ifif; M ATTORNEYS Nov. 1, 1966 TETUYA lSEKl 3,282,721

LEATHER-LIKE CLOTH AND ITS PREPARATION Filed April 16, 1964 4 SheetsSheet 4 INVENTOR BY u} M 41 r W ATTORNEYS United States Patent 3,282,721 LEATHER-LIKE CLOTH AND ITS PREPARATION Tetuya lseki, Sugin'arni-ku, Tokyo, Japan, assignor, by direct and mesne assignments, to Tetuya Iseki, Tokyo, Japan, and T. Takase Company, Honolulu, Hawaii, a partnership Filed Apr. 16, 1964, Ser. No. 360,223 4 Claims. (Cl. 117-7) The present invention relates to a leather-like cloth having excellent permeability, warmth retentivity and suitable hygroscopicity, in addition to the usual favorable characteristics of leather, and to a method for producing such cloth by using woven fabric and leather powder.

An object of the present invention is to provide a leather-like cloth having a leather-like feel, and also having excellent permeability, warmth retentivity and suitable internal hygroscopicity which could never be expected of a natural leather, by properly selecting the woven fabric according to the use to be made of the cloth.

Another object of this invention is to provide a leatherlike cloth which can be used for such articles as various garments, shoes, cases, globes, hats, Wall-cloth and chaircovers.

Printing on leather has generally met with many difiiculties. However, because the method of the present invention provides a leather-like cloth having the excellent characteristics as mentioned above, it is possible to impart optional printing patterns to the leather cloth. It is particularly significant that patterns having unusual shading and feeling can be obtained by gravure printing of the leather-like cloth of the present invention.

The process of the present invention can be carried out by the following steps:

(1) Raising the nap on one or both faces of a woven fabric such as cotton cloth, silk cloth, flax cloth, [fur cloth, synthetic fiber cloth and piled woven cloth to a nap height of about 0.3- mm.;

(2) Laying or paralleling the nap in one direction by, for example, brushing said fabric;

(3) Stretching said fabric 45% in either the warp or the weft direction or in both directions while adjusting the angle of inclination of the nap to the raised face or faces to a value in the range of about 5 to (4) Applying a bonding agent comprising a copolymer of butyl acrylate and styrene onto the face having the said laid nap thereon in an amount such that the applied bonding agent covers /2 to the full length of the nap length so as to prevent, as much as possible, the penetration of the bonding agent into the fabric;

(5) Spreading or scattering leather powder prepared by pulverizing waste leather (of, for example, sheepskin or buckskin) over the said face by a suitable method such as spraying or sprinkling;

(6) Pressing the thus processed .fabric at a pressure of about 810 kg./m to firmly stick the applied powder to the fabric;

(7) Heating the pressed fabric at a temperature of about 140-150 C. for 3-5 minutes to set the bonding agent. The fabric is then immersed in warm water at about 30 C. or subjected to steaming to shrink the processed fabric to a size which is the same as, or smaller than, the original fabric, thereby increasing the amount of leather powder per unit area and producing leather-like creases.

By employing the above process, a leather-like cloth having extremely good feeling, air-permeability and warmth retentivity is obtained.

The drawings attached will help to give clearer understanding of the present invention. In the drawings, FIG. 1 is an enlarged sectional view of the woven fabric cut in 3,282,721 Fatented Nov. 1, 1966 the warp direction, wherein there is shown the warp 1 and the weft 2. FIG. 2 is a sectional view of the woven fabric cut in warp direction as shown in FIG. 1, showing the state of the fabric with the nap raised to a length of about 1 mm., wherein there is shown the nap 3 the length of which is about 1 mm.

In the following FIGS. 3a to 8b, the section in the warp direction is designated by a and that in the weft direction by b. FIGS. 3a and 3b are sectional views showing the raised face shown in FIG. 2. FIGS. 4a and 4b are sectional views showing the fabric as shown in FIG. 2 and FIG. 3 after it has been stretched about 6% in the direction of the weft. FIGS. 5a and 5b are sectional views showing the stretched fabric with the )naps laid down at an angle of 510 to the warps. FIGS. 6a and 6b are sectional views of the fabric shown in FIG. 5, with a bonding agent 4 applied to the nap of the fabric to the extent such that the bonding agent covers about the length of the nap. FIGS. 7a and 7b are sectional views of the fabric as shown in FIGS. 60 and 6b to which has been applied a uniformly scattered leather powder and which has been pressbonded. FIGS. 8a and 8b are sectional views of said fabric after it has been shrunk by immersion in warm water in an amount about 10% based on the length of the stretched fabric. Leather-like creases 6 are produced when the cloth is shrunk, and very narrow spaces 7 are formed between the applied maps and very narrow spaces 9 are created between the warp and resin binding layer.

The feel of the cloth imparted by the leather-like creases varies according to the kind of fibers which constitute the fabric-such as animal fibers, vegetable fibers, synthetic fibers or mineral fibers (like asbestos fibers, etc.). It also varies depending upon the thickness of the fabric, and the nap length varies in accordance with the weave of the fabric, such as plain weave, twill weave, satin weave, nonwoven fabrics or a variety of hosiery goods. Sufiicient raising of the fabric results in a large shrinkage, thick texture and large creases after finishing. On the other hand, a fabric of short nap length has small shrinkage, thin texture and small creases after finishing.

It was found that if leather powder is blended into the bonding agent, the density of the coating is enlarged, and the leather-like feeling and dyeing properties with respect to acid colors are greatly improved. If a color pigment is incorporated in the bonding agent, the color shade of the product cloth is improved. This turns out to be advantageous in dyeing and finishing.

The present invention thus provides a leather-like cloth having an appearance closely analogous to natural leather, with strength, flexibility, tensile and tearing strength, airpermeability and warmth retentivity equal to or better than natural leather. In this respect, the present leatherlike cloth is quite different from hitherto available leatherlike materials generally formed from synthetic polymers.

Raising of the face or faces of the fabric is for the purpose of ensuring a firm adherence of leather powder to the fabric, and to impart a good feel and appearance to the cloth. Such a procedure is also necessary to produce the narrow spaces between the leather powder layer and the fabric which serve to impart air-permeability and the warmth retaining property to the cloth.

Favorable results are obtained when the nap length is restricted to a value in the range of 0.3-5 mm., preferably 0.S1 mm. When the leather powder-applied fabric is treated in warm water, the density of the leather powder is increased in proportion to the shrinkage of the fabric. When the fabric is shrunk in excess of a certain amount, creases are produced on the leather powder-applied faces of the fabric. The produced creases provide a feel closely analogous to natural leather.

A suitable amount of leather powder to be scattere over the coated face of fabric is 50-100 g./m.

Leather powder used for the present invention can be prepared by pulvenizing waste leather into fine particles with a size of 3-10 meshes (U.S. Standard) by a conventional pulverizer. Leather powder obtained from waste leather (cowhide, sheepskin, deerskin, etc.) is first sorted out into grain l-ayer powder and corium layer powder, and, while maintaining the water content in the range of 50- by weight, 0.1% of fungicide is added. The mixture is subjected to the action of a stamp mill and decomposed into fiber-like pieces, which are dried to reduce the water content to about and then pulverized by an impact hammer mill. Leather powder to be used for the present invention can also be prepared by the following method. First the waste of leathers, such as cowhide, sheepskin and deerskin are sorted out into grain layer and corium layer, then a mixture of a water-soluble thickening agent and a fungicide, for example, a paste composed of 1.5 kg. of rice powder, 1.5 kg. of dextrin, 7 kg. of water and 10 g. of phenyl mercury naphthenate (fungicide), is blended with 80-90 kg. of leather waste. This mixture is then pressed into a lump, dried sufficiently and pulverized into fine particles by, for example, an abrasive grinder.

A bonding agent suita-ble for bonding the leather powder to the naps of the fabric in the present invention is a copolymer of butyl acrylate and styrene.

Viscosity of the bonding agent to be used must be carefully selected. In general, it should preferably be in the range of about 2,000 to 15,000 cps. Concentration of the bonding agent must therefore be selected in conformity with the viscosity selected.

Thickness of the bonding agent to be applied should be in the range of about 0.2-0.6 mm. Favorable results are obtained when the application of the bonding agent is restricted to such an extent that it covers from /2 to the full nap length, with a view to preventing, as much as possible, the penetration of the bonding agent into the fabric. If the bonding agent penetrates into the fabric, the shrinking and permeability of the fabric are greatly reduced, consequently making it hard to attain the objects of the present invention. On the other hand, if the powder is bonded only at the tip of the nap at a point spaced from the fabric, the part under the powder coating formed by the bonding agent becomes spongy, resulting in a weakening of the strength of the coating and eventually the occurrence of cracks.

Stretching of the napped fabric in the warp or weft direction is intended to produce ample leather-like creases on the leather powder-applied faces. Creases are produced when the drawn cloth, after being pressed and dried, is immersed in warm water or subjected to steaming so as to be shrunk. Shrinkage of the fabric increases the amount of leather powder per unit area. When it exceeds a certain limit, creases are produced, along with narrow spaces between the leather powder and the fabric. These are important factors in imparting permeability, warmth retentivity and suitable hygroscopicity to the cloth.

For example, if a fabric having a width of 96.5 cm. is stretched widthwise to 102 cm. and then subjected to said processing treatment, the width of the cloth is shrunk to about 91.5 cm. Permeability obtained varies according to the extent and mode of application of the bonding agent in said processing treatment. The extent of application of the bonding agent should be such as to produce narrow spaces between the fabric and the leather powder layer so as to impart permeability to the cloth.

A comparison of the sizes of the fabric used as the starting material and the sizes of the processed cloth is given in Table I below to illustrate the amount of shrinking. A plain weave cloth comprising blended yarn of 70% of viscose rayon staple and 30% of polyvinyl alcohol fiber staple was used.

TABLE I Size of body fabric before Size of body fabric after processing processmg Thickness Width Length Thickness Width Length (min) (cm.) (m.) (min) (cm.) (m.)

The thus obtained leather-like cloth of this invention is then, subjected to bleaching, dyeing if necessary, drying, sufficient oiling and finally brushing.

According to the present invention, it is possible to produce articles having different feels depending on the desired uses by changing the kind of fibers which constitute the fabric, the structure, nap length of the fabric, the composition and quantity of the bonding agent, and the quantity of powder scattered on the fabric.

It was found that if the fabric is first raised on one face and then, after shrinking and drying, raised on the other face, better feeling is obtained than the fabric raised on both faces simultaneously.

It was also found that a leather-like cloth having unique feeling with appearance resembling suede or buckskin is obtained when the powder-applied faces are re-raised lightly.

A comparison of the characteristics of the leather-like cloth of the present invention (A, B and C) thus obtained and those of tanned deerskin is shown in Table II below.

TABLE II Materia1 Item Leather-like cloth of Tanned the present invention deerskin A B C Weight (g./rn. 3,676 328. 7 946. 7 23.52 Thickness (mm) 1.20 1. 22 0.86 1. 00 Apparent specific gravity (g./cm. 0.31 0.27 O. 40 0.29 Bending strength:

Warp (mg/cm.) 310 775 1, 499 1,501 Weft (ing./cm.) 1, 286 1, 791 1, 790 Breaking abrasive strength: 1

Warp (turn) 8, 533 1, 405 1, 419 1, 501 Weft (turn) 6, 158 1, 213 1, 456 1, 551 Abrasive strength (mg.) 3. 3 5.6 5. 2 5. 6 Abrasive ratio (percent) 0. 69 1. 31 0.42 0.48 A11 permeability (cc./cm. /sec.) 2. 31 0.34 0.38 0.38 Warmth retentivity (percent) 65. 1 62. 5 61. 7 62. 4

restrict the scope of the present invention.

EXAMPLE 1 Both faces of a plain weave cloth formed from blended yarn of polyvinyl alcohol fiber staple and viscose rayon staple (wherein the count of the warp and the filling were respectively 30s/1 and 30s/2, density of the cloth was 50 x 58/inch, width of the cloth was 121.9 cm. and the length of the cloth was 42.5 m.) were raised to a nap length of about 0.7 mm., then the raised fibers were paralleled in one direction. The cloth was then tentered by a pin tenter to stretch the cloth in an amount of 4 to 5% in both the warp and weft directions. Thereafter, a bonding agent having a viscosity of about 15,000 cps. was applied to one raised face uniformly covering about /3 the nap length by an appropriate method, for

example using a rotating roll, then leather powder was uniformly sprayed over the bonding agent-coated face in an amount of 100 g./m. The thus treated cloth was subjected to light brushing, pressed by rolls at a pressure of 8-10 kg./m. to bond the leather powder layer, then heated at 140-150 C. for 3-5 minutes to set the bonding agent, and immersed in warm water at 30 C. for about 20 minutes to shrink the cloth sufficiently.

The shrunk cloth was dyed to the desired shade, and after the cloth was dried, the face covered with leather powder was again raised lightly and then given a brushing. In accordance with the present invention, it is also possible to print the cloth instead of dyeing it.

In the examples that follow, processes of making the cloth will be described to produce cloth for various uses. However the principal steps in each example are just the same as in Example 1.

EXAMPLE 2 Leather-like cloth for blouses A plain weave cloth made of blended spun yarn comprising 70% of viscose rayon staple and 30% of polyvinyl alcohol fiber staple (the counts of warp and weft of which were respectively, 30s/ 1 and 30s/ 2, the density of which was SO/inch (warp) x SO/inch (weft), and the thickness, width and length of which were respectively 0.5-0.6 mm., 97 cm. and 40 m.) was raised to a nap length of 0.2-0.3 mm., then the same bonding agent as in Example 1 was applied to the raised face Thick clothing materials such as overcoats and jumpers A twill weave cloth made of blended yarn comprising 70% of viscose rayon staple and 30% of polyvinyl alcohol fiber staple (the count of warp and weft of which were respectively 20s/l and 20s/2 and the thickness, width and length of which were respectively 0.7-1 mm., 97 cm. and 40 m.) was used as the body fabric. The cloth was raised to a nap length of 0.3-0.5 mm., and then the bonding agent was applied to the raised face to the full nap length so that the bonding agent did not penetrate into the cloth. Then pulverized grain layer powder was applied to said bonding agent-coated face in an amount of 100 g./m. when it was applied to only one face of the cloth and 50 g./'tn. x 50 g./m. when applied to both faces.

Thereafter, the cloth was treated in the same manner as in Example 1. Resulting therefrom was a clothing material having largely developed creases which give thickness to the cloth, air permeabiilty, warmth retaining characteristics and, because of the twill, excellent pliability. Thus the produced cloth turned out to be best fitted for the desired object.

EXAMPLE 4 Leather-like cloth used for shoes and cases A twill weave cloth composed of polyvinyl alcohol fiber spun yarn (the count of which cloth was 20s/l (warp) and 20s/2 (weft), the density of which was 80 x 55/in., and the thickness, width and length of which Was respectively l-2 mm., 97 cm. and 40 m.) was used as the body fabric. Said cloth was raised to a nap length of 0.3-0.5 mm., and then the bonding agent was applied to the raised face covering the full length of the raised fibers. Thereafter, powder of the grain EXAMPLE 5 Leather-like cloth for gloves A thin silk cloth (having a count of warp and weft of 140/2 and 92/2, and a density of /inch x 69/inch) was used as the body fabric with a view to making the raised fibers dense. The nap on the body fabric was raised so as to be 0.2-0.3 mm. in length, then treated with warm water to shrink the said cloth sufficiently (to about 95 cm. in width from the original cm.), and then, after it was dried, it was stretched by tentering so it was 100-110 cm. in width. While the cloth was in the stretched state, the face on which the nap was not raised was gigged, effecting nap control in one direction. Thereafter, a bonding agent was uniformly applied to said raised face to cover from /2 to the full nap length. Then grain layer powder with a particle size of 3-5 mesh was uniformly scattered over the raised face. The thus treated cloth was then pressed slightly by rolls under a pressure of 8-10 kg./m. to bond the leather powder to the body cloth, was heated at -150 C. for 3-5 minutes to set the bonding agent, was immersed in 30 C. water and shrunk to about 94 cm. in width, and was then dried. The resulting cloth had fine creases and good elasticity.

EXAMPLE 6 Leather-like cloth for wall and chair covering A plain weave cloth made of blended yarn comprising 70% of viscous rayon staple and 30% of polyvinyl alcohol fiber staple (the thickness of which was 0.6 mm., and having a width of 100 cm., a length of 42 m. and a nap length of 0.3-0.5 mm.) was used as the body fabric. A bonding agent was applied to the raised face to cover from /2 to the full nap length, and then leather grain layer powder was scattered over the bonding agent-coated face in an amount of 60 g./m. Corium layer powder can be applied in an amount of 100 g./m. when the cloth is intended for use as a wall-cover. In this case, an anti-flaming and fireproofing finish should also be applied. It is also possible to use fabrics having twill weave or satin weave for wall and chair covering cloth instead of said plain weave cloth. The resulting cloth, with well developed creases and suitable thickness, is well suited for wall and chair coverings.

It is also possible to print the cloth prepared by the present invention.

What is claimed is:

1. A leather-like cloth comprising a shrunk fabric base having raised nap on at least one face thereof having a length of from 0.3 to 5 mm. high, a layer of set bonding agent covering at least part of the length of the nap, said fabric base being substantially free of bonding agent, and a layer of fine leather powder slightly compressed and firmly secured to the bonding agent, said leather powder layer having leather-like creases therein.

2. A leather-like cloth as claimed in claim 1 in which said leather powder layer and said bonding agent layer have narrow openings therethrough, thereby making the said cloth permeable.

3. A process for producing a leather-like cloth, which comprises the steps of raising the nap on at least one face of a fabric to an extent that the nap length is from 0.3 to 5 mm. high, applying a bonding agent onto the face having the nap thereon and covering at least a part of the length of the nap without substantially impregnating the fabric, forming a layer of leather powder on the thus coated face by scattering fine leather powder thereover, applying a light pressure to the thus processed fabric to firmly secure the powder to the fabric, setting the bonding agent, and wetting the fabric to shrink the thus coated fabric and thereby increase the amount of powder per unit area of the fabric and produce leatherlike creases therein.

4. A process for producing a leather-like cloth, which comprises the steps of raising the nap on at least one face of a woven fabric to an extent such that the nap length is from 0.3 to 5 mm. high; laying the nap in one direction so that it is at an angle of from 510 to the face of the woven fabric; stretching the said woven fabric in at least one direction by an amount of from 3-8% of the dimension in said direction; applying a bonding agent for bonding leather powder to the nap onto the face 20 having the said laid nap thereon to a depth sufficient to cover from one-half to the full length of the nap, scattering fine leather powder over the thus coated face in an amount of from 50-100 g./m. applying pressure to the thus processed fabric of from 8-10 kg./m. to firmly secure the powder to the fabric; drying the pressed fabric; and immersing the dried fabric in warm water to shrink the thus coated fabric and thereby increase the amount of leather powder per unit area and produce leather-like creases therein.

References Cited by the Examiner UNITED STATES PATENTS 1,425,307 8/1922 Wilson 117-11 1,922,020 8/1933 Van Voorhis 117-7 2,836,509 5/1958 Berry 117-7 2,917,421 12/1959 Miller 161-63 2,963,381 12/1960 Leirnbacher 1177 2,997,773 8/1961 Roth et a1 2876 3,041,707 7/1962 Perri 16l-67 3,074,835 1/1963 Gordon 16167 3,114,191 12/1963 Chapin 28--76 FOREIGN PATENTS 519,420 3/ 1940 Great Britain.

ALEXANDER WYMAN, Primary Examiner.

EARL M. BERGERT, A. I. SMEDEROVAC, G. D.

MORRIS, Assistant Examiners. 

1. A LEATHER-LIKE CLOTH COMPRISING A SHRUNK FABRIC BASE HAVING RAISED NAP ON AT LEAST ON FACE THEREOF HAVING A LENGTH OF FROM 0.3 TO 5 MM. HIGH, A LAYER OF SET BONDING AGENT COVERING AT LEAST PART OF THE LENGTH OF THE NAP, SAID FABRIC BASE BEING SUBSTANTIALLY FREE OF BONDING AGENT, AND A LAYER OF FINE LEATHER POWDER SLIGHTLY COMPRESSED AND FIRMLY SECURED TO THE BONDING AGENT, SAID LEATHER POWDER LAYER HAVING LEATHER-LIKE CREASES THEREIN. 